157 



Remarks.— This form was described as early as in the year 1767 by 

 Linnseus as Oniscus oceanicus, and has subsequently been recorded by Leacli and 

 Bosc under different specific names. It is the largest of our indigenous Oniscoida, 

 and is moreover easily recognizable by the strongly built antennae and the struc- 

 ture of the uropoda. 



Occurrence. — Along the western coast of Norway this form occurs rather 

 plentifully, and extends northwards at least to the Trondhjem Fjord. In the 

 inner part of the Christiania Fjord, on the other hand, I have never met with 

 it, and it would seem therefore that it deserves its specific name, being appar- 

 ently restricted to those coasts that are open to the oceans. It is always found 

 close to the shore, just above high-water-mark, beneath decaying algse and stones, 

 feeding, it would seem, both on animal and vegetable matter. When alarmed, it 

 runs away with great agility, to conceal itself in the crevices of the rocks, and 

 beneath stones. 



Distribution. — Coasts of Denmark, Prussia, Belgium, France, Sjiain, Britain, 

 Faro Islands. 



Gen. 2. Ligidium, Brandt, 1833. 



Syn: Zia, Koch. 



Generic Characters. — Body oblong, rather convex, attenuated behind. Ce- 

 phalon evenly rounded in front. Lateral parts of mesosome less prominent than 

 in Ligia, and not defined from the corresponding segments by any distinct groove. 

 Metasome comparatively small and abruptly contracted, with the last segment of 

 inconsiderable size and without any epimeral plates. Eyes large and convex. 

 Antennulas less rudimentary than in Ligia, and distinctly projecting in front. 

 Antennae less strongly built than in that genus, though of a very similar struc- 

 ture. Mandibles with a restricted number of penicils, and without any ciliated 

 lappet behind the cutting part. Maxillipeds more slender than in Ligia, with 

 the terminal part less expanded, epignath narrow linguiform. Legs very slender, 

 and greatly increasing in length posteriorly. Opercular plates of pleopoda very 

 thin, without any obvious branchial structure. Uropoda not very large, basal part pro- 

 duced at the end inside to a conical process carrying the inner ramus, the latter, 

 as a rule, smaller than the outer, and provided with 2 long and slender apical 

 bristles. 



